Mitteilung zur Benzolselenonsäure

Paetzold, R.; Lienig, D.

doi:10.1002/zfch.19640040512

Cited by 9 publications

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“…This is due to the rapid conversion of 10 to the selenonium selenonate salt 11, followed by further oxidation to 12 and finally to 13 in the presence of hydrogen peroxide (Scheme 2). Several earlier reports of the preparation of 12 [84,85] were subsequently shown to be in error, as the products proved to be the salt 11, as later confirmed by x-ray crystallography [77]. It was therefore of interest to investigate the similar oxidation of ebselen to see whether products analogous to 11-13 would again be formed.…”

Section: Oxidation Of Ebselenmentioning

confidence: 97%

Chemistry Related to the Catalytic Cycle of the Antioxidant Ebselen

et al. 2023

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The antioxidant drug ebselen has been widely studied in both laboratories and in clinical trials. The catalytic mechanism by which it destroys hydrogen peroxide via reduction with glutathione or other thiols is complex and has been the subject of considerable debate. During reinvestigations of several key steps, we found that the seleninamide that comprises the first oxidation product of ebselen underwent facile reversible methanolysis to an unstable seleninate ester and two dimeric products. In its reaction with benzyl alcohol, the seleninamide produced a benzyl ester that reacted readily by selenoxide elimination, with formation of benzaldehyde. Oxidation of ebselen seleninic acid did not afford a selenonium seleninate salt as previously observed with benzene seleninic acid, but instead generated a mixture of the seleninic and selenonic acids. Thiolysis of ebselen with benzyl thiol was faster than oxidation by ca. an order of magnitude and produced a stable selenenyl sulfide. When glutathione was employed, the product rapidly disproportionated to glutathione disulfide and ebselen diselenide. Oxidation of the S-benzyl selenenyl sulfide, or thiolysis of the seleninamide with benzyl thiol, afforded a transient thiolseleninate that also readily underwent selenoxide elimination. The S-benzyl derivative disproportionated readily when catalyzed by the simultaneous presence of both the thiol and triethylamine. The phenylthio analogue disproportionated when exposed to ambient or UV (360 nm) light by a proposed radical mechanism. These observations provide additional insight into several reactions and intermediates related to ebselen.

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Section: Oxidation Of Ebselenmentioning

confidence: 97%

Chemistry Related to the Catalytic Cycle of the Antioxidant Ebselen

et al. 2023

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Functional groups containing selenium and tellurium in various oxidation states

Sonoda

1986

PATAI'S Chemistry of Functional Groups

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The Unexpected Role of Se^VISpecies in Epoxidations with Benzeneseleninic Acid and Hydrogen Peroxide

et al. 2020

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Benzeneperoxyseleninic acid has been proposed as the key intermediate in the widely used epoxidation of alkenes with benzeneseleninic acid and hydrogen peroxide. However, it reacts sluggishly with cyclooctene and instead rapidly decomposes in solution to a mixed selenonium–selenonate salt that was identified by X‐ray absorption and 77Se NMR spectroscopy, as well as by single crystal X‐ray diffraction. This process includes a selenoxide elimination of the peroxyseleninic acid with liberation of oxygen and additional redox steps. The salt is relatively stable in the solid state, but generates the corresponding selenonic acid in the presence of hydrogen peroxide. The selenonic acid is inert towards cyclooctene on its own; however, rapid epoxidation occurs when hydrogen peroxide is added. This shows that the selenonic acid must first be activated through further oxidation, presumably to the heretofore unknown benzeneperoxyselenonic acid. The latter is the principal oxidant in this epoxidation.

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Mitteilung zur Benzolselenonsäure

Cited by 9 publications

References 1 publication

Chemistry Related to the Catalytic Cycle of the Antioxidant Ebselen

Chemistry Related to the Catalytic Cycle of the Antioxidant Ebselen

Functional groups containing selenium and tellurium in various oxidation states

The Unexpected Role of Se^VISpecies in Epoxidations with Benzeneseleninic Acid and Hydrogen Peroxide

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Mitteilung zur Benzolselenonsäure

Cited by 9 publications

References 1 publication

Chemistry Related to the Catalytic Cycle of the Antioxidant Ebselen

Chemistry Related to the Catalytic Cycle of the Antioxidant Ebselen

Functional groups containing selenium and tellurium in various oxidation states

The Unexpected Role of SeVISpecies in Epoxidations with Benzeneseleninic Acid and Hydrogen Peroxide

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The Unexpected Role of Se^VISpecies in Epoxidations with Benzeneseleninic Acid and Hydrogen Peroxide